Determinación de la presencia de Actinobacillus Pleuropneumoniae y su relación con las medidas de bioseguridad en el control de signos clínicos de la enfermedad en explotaciones porcinas brasileñas

Abstract

Twenty farms have been selected in the main pig producing areas of Brazil. The criterion was that they had a positive serology against ApxIV. The presence of symptoms compatible with pleuropneumonia was determined, samples were taken to isolate the pathogen and it was serotype by PCR. In addition, a biosafety audit was conducted, based on a traffic light system evaluating external, internal and containment biosecurity. The reproductive and productive parameters in transition and bait were taken and a model farm was also selected to monitor the serotypes present and the sacrificial lesions compatible with pleuropneumonia. Symptoms were found in 40% of the farms included in the study. The farms without symptoms had better reproductive and productive yields in transition and bait, which led to a reduction in the cost of production of between 3-11 euros / pig slaughtered in asymptomatic farms. The bacterium was found in 78% of the samples when the serogroup typing technic was used. When serotypes were typed individually, the predominant serotype was 7 (51%), followed by 15 (22%) and 4 and 5 (11%). The isolated strains showed resistance to penicillin, tetracycline, oxytetracycline and amoxicillin, mainly, reaching up to 4 resistances simultaneously. In farm G serotype 7, 4 and 12 were found in the 2017-2019 period, and there was some difference in the number of resistances in the strains; In 2019, they all had at least three resistances. Pleurisy lesions compatible with actinobacillosis were found in 0.09-6.24%, with an obvious seasonality, being more prevalent in March and the November-January period. When evaluating biosecurity, significant differences were found in the score obtained by farms with and without symptoms. The profile obtained for symptomatic farms was: a farm that introduces replacement sows of more than one origin, where the recovered sick piglets return to the flow, neither gloves nor boots nor specific clothing that does not leave the farm are not used, it is not It does everything inside everything outside the premises, the cleanliness is poor, it has low replacement and aged census. As a consequence of the disease, these farms will have a high mortality in bait, a high transformation rate and more than 4 dollars of medication per pig; and they will also have a hospital. With respect to internal biosecurity, the type farm with symptoms is a farm without perimeter fencing and therefore allows access to roads and drivers to its facilities, which does not use bristle baths when moving from one.